Generally, the present invention relates to the distribution of subscriber program material, and more particularly to distribution of television program material using wireless broadband loops and a bidirectional antenna array.
Conventionally, the use of wireless communication is restricted to cellular telephone systems for voice and limited data service. Recently, however, wireless communication services are being used for unswitched "broadcast" television distribution. These systems use a cellular structure with each cell transmitting in the direction of potential subscribers. Two of these systems include an early analog approach, referenced in "The M.sup.3 Saxmundham Demonstrator-Multichannel TV Distribution by mm-Waves," M. Pilgrim, R. P. I. Scott, R. D. Carver, and B. J. Ellis, British Telecom Tech., J. Vol. 7 No. 1, Jan. 1989, and a digital broadcast approach, Application of Hye Crest Management, Inc. before the FCC, File No. 10380-CF-P-88, released Jan. 18, 1991, the latter being designed to take advantage of highly compressed digital video/audio codecs.
These approaches as well as other more recent developments in television and data signal broadcasting, allow subscribers to select information programs from a set of broadcast program materials. Once selected, a data stream of program material is received by the subscriber in a continuous downstream feed. Video on demand and pay-per-view systems for example, permit users to select a broadcast channel transmitting a movie or other program material for viewing. The channel is selected at the viewer's home, and the program is received at a designated, scheduled time. Conventionally, the downstream data flow is controlled by the distribution source, and the subscriber has little or no input as how the data stream is received. In other words, while the subscriber can request the program material or movie, he cannot start or stop the stream once it has begun. In addition, the subscriber cannot affect the downloading speed or sequence of the downloaded signal. Further, because conventional transmission facilities continually broadcast the material on a given channel, scrambling or blocking techniques are often required to prohibit unauthorized access of the material.
Conventional broadcast systems of this type also do not offer an upstream signaling capability that allow the user to transmit data via the network. If available, this upstream signaling capability could permit subscribers to utilize the high bandwidth transmission rates of a centralized control center for their own personal broadcast. Services, such as desktop video conferencing and home data transmission uplink, could be initiated from the subscriber's location and transmitted using a two-way communication center.
There is therefore a need for an economical approach for distributing a wide range of subscriber services to customers without access to conventional broadband wireline distribution systems. The solution should provide a low-powered, high bandwidth switched service system with the ability to provide the services to a large number of subscribers. The system should give subscribers both upstream and downstream signaling capabilities with control over the downstream program signal once it is requested. Preferably, the solution should also allow subscribers to use the capabilities of the two-way broadcasting center via upstream signaling. Finally, the solution should effectively deny unauthorized access to source material.